1. Field of the Invention
The present invention generally relates to typewriter and data input devices, and more specifically, to a one-handed keyboard.
2. Description of the Prior Art
Numerous keyboards for typewriters and the like and data entry devices have been proposed. In a first class of such devices, the total number of keys are greatly reduced from the number typically found on a typewriter or computer keyboard. Such devices, however, contemplate the use of both hands. To achieve such result, each of the keys are normally arranged in one large cluster or two small clusters--one for each hand--with each key representing a multi-function key which can be actuated to generate two or more alphanumeric characters or symbols. Patents which disclose devices in this category are typified by the following: U.S. Pat. No. 2,532,228 to Hesh for an electrically operated typewriter; U.S. Pat. No. 4,449,839 to Bleuer for a keyboard with elongated keys; U.S. Pat. No. 3,633,724 to Samuel for electric typewriter and keyboard arrangement; and U.S. Pat. No. 4,067,431 to Whitaker for a combinational keyboard. Other devices disclosing multi-function keys are disclosed in U.K. Pat. No. 2,064,187 to Eilam for a chordic keyboard and U.S. Pat. No. 345,565 to Baldrige.
There have also been proposed a number of small hand-held keyboards. For example, a keyboard for a hand-held computer is disclosed in IBM Technical Disclosure Bulletin of Vol. 27, No. 10A, March 1985, where a hand-held computer keyboard is disclosed which can be actuated by the fingers of one hand while the computer is held in the palm of the hand. In U.S. Pat. No. 4,253,774 to Hanakata et al., an information output device is disclosed wherein a keyboard includes keys corresponding to the characters to be reproduced and for the selection of characters. This output device is sufficiently small that it can be worn on one hand, like a watch, and actuated or operated by the other hand.
Numerous designs have also been proposed for single handed use. Such a device, for example, a disclosed in U.S. Pat. No. 725,855 to Loyd. This patent discloses a typewriter which can be worn on a person's arm and operated by the other arm. A hand-held data input device is disclosed in IBM Technical Disclosure Bulletin Vol. 26, No. 11, April, 1984, which is in the nature of a pistol-grip hand-held device. In Siebel et al U.S. Pat. No. 3,022,878, a communication device is disclosed wherein each finger of a user's hand is engaged with a separate multi-position switch. By moving the tips of each of the individual fingers, therefore, different code or characters can be generated. In International Publication No. WO82/01345 of Croczynski, a hand-bound keyboard is disclosed which is actuatable by the fingers of the operator. The keyboard may be actuated without any hand or arm movement of the operator, means being provided for immobilizing the keyboard with respect to the palm and back of the hand while letting the fingers free to move. Each key is arranged so as to be actuated by a single finger. Also, illustrative of this art is German Pat. No. 308,048 to Mamerow. The device in the aforementioned German patent is a hand-held multi-key device which can be selectively actuated by the five fingers of the hand. No movements of the hand are involved.
Finally, simplified keyboards have been disclosed which utilized hand rests to provide the user with a place to rest his hands during typing. Such keyboards are disclosed in U.S. Pat. Nos. 4,081,068 and 4,201,489 to Zapp. In these patents, a hand rest is disclosed for the ball of the thumb or wrist of the hand, on which the hand of the operator can rest continuously to support his hand during actuation of the keyboard. Means are provided for adjusting the positions of the hand rests to dispose the finger tips of the fingers in natural dispositions in relation to the keys to be actuated, without being tensioned.
Thus, while the prior art has disclosed multi-function keyboards and small, hand-held or single hand devices, the number of alpha numeric characters, symbols and/or functions which have been attainable has been limited. There is a practical limit on the number of characters or functions that can be accessed by five fingers of one hand. The purpose of the present invention is to substantially increase the number of alpha-numeric characters and/or functions which are accessible by one hand so as to provide a full-function typewriter and/or computer data input terminal, without sacrificing simplicity of use and speed of operation.